Motion Characteristic Analysis And Parameter Optimization On Vibration Mill With Modified Exiciting Method

Vibaration mill is a typical equipment which used to prepare powder particles. It has several advantages such as simple structure, easy operation, lower energy consumption and higher output. Vibration mill is especially suitable for graphite, chemical, mining, ceramics and other industries. It has been widely used in the preparation of ultrafine powder at home and abroad. The mill's body will be driven by vibration motor to move at a certain vibration frequency and amplitude after starting the mill. So the material can be broken and refined through impact, friction and shear which produced by grinding medium. During the grinding process of material, the choice of vibration amplitude and frequency is very important. The efficiency of mill and the grinding effect of particles are directly affected by vibration amplitude and frequency. At present, a advanced vibration mill with wide band vibration frequency has been established through improving the vibration exciter structure. In the improvement, relationship between motion characteristics and excitation parameters of the body is studied while the effect of body motion on grinding mechanism and particle breakage is not taken into consideration. And the control of the vibration frequency is ignored. Thus the efficiency of mill and the applicability in engineer have not been improved significantly. Therefore, the theoretical and experimental research on the optimization method of parameters of vibrating mill is carried out from crushing mechanismand motion characteristics in this paper. And the effectiveness of the research results was verified by the physical prototype grinding test. Then based on the multi objective programming model, work of vibration mill is improved to develop a new type of high efficiency vibrating mill with better grinding effect and stronger engineering applicability.At first, the working principle of vibration mill is a analyzed, the technology of superfine powder as well as mill's domestic and international development present situation is summerized in this paper. Also, the problems existed during ginding for ultrafine powder are dissected. So, the research focus of the paper is determined.Secondly, based on the working principle of mill, the objective optimization parameters are determined, the motion characteristics of grinding medium are studied with single particle crushing theory and dynamic theory of grinding medium. And the relationship between grinding effect and optimization objective parameters is analyzed quantitatively based on EDEM. An algebraic coupling relationship between motor speed, excitation block radius and material crushing effect is built through statistical regression analysis of test data, so as to provide theoretical support for the optimization of the performance parameters of vibrating mill.Thirdly, according to simplified mechanical model of traditional mill, motion characteristics of mill is discussed, the nonlinear behavior of mill's motion is analyzed. Then a new type of vibration mill with double variable excitation is presented in this paper. The ADAMS prototype model of this new type vibration mill is established and the validity of model is verified by the laser displacement test. Multi condition simulation test are conducted based on Adams model. So the influence of motor speed, excitation block radius on grinding effect is analyzed. Motion states of mill under each condition are compared in order to determine the optimum radius ratio and motor output speed. Diamond powder is chosen as test material to carry out 3 physical prototype grinding experiments and the particle size and distribution of product powder are compared. Results show that the average particle size of product after optimization is smaller and the fine particle content is more. So the validity of optimization is verified, the study on optimization method of ultrafine grinding is realized.Finally, based on the results of simulation analysis and physical prototype test under multi condition combination optimization, multi objective programming model of vibration mill is proposed to describe relationship between motor speed, grinding block radius and grinding effect. Taking multi condition optimization as numerical example, multi objective programming method is used to solve the case. The performance indicators of mill after multi objective programming are all increased. Therefore, the effectiveness and feasibility of this proposed method are verified, the engineering applicability of vibrating mill is improved.